(Left) Small interfering RNAs (siRNAs), processed by Dicer, play a role in RNA-directed DNA methylation (RdDM) in addition to mRNA degradation. These RNAs combine with DNA methyl transferases (DMTases) to methylate cytosine residues in promoter regions, resulting in "silent" heterochromatin.

(Right) Dicer can also produce microRNA (miRNA) that binds to complementary 3'-untranslated regions (UTRs) of mRNA, inhibiting translation.